Abstract: The present invention relates to a communication interface (200) for supporting communication between a wireless device (101, 102, 103) and a server (121) over a low power wide area network, LPWAN, comprising: an untrusted execution part (201) configured to operate in accordance with an LPWAN communication protocol stack (203) including at least one secured LPWAN protocol using cryptographic primitives; a memory (205) for storing computer code (206) and at least one cryptographic key (207, 208, 209) in an encrypted form; a trusted execution part (202) incorporating a root secret (210) for decrypting the at least one cryptographic key (207, 208, 209) from the memory (205), wherein the trusted execution part (202) is configured to execute the cryptographic primitives of the at least one secured LPWAN protocol using the decrypted cryptographic key and computer code (206) from the memory (205).